JP2002200975A - Brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continue a control by a brake hydraulic control device even if a master shutoff valve faultily fails to open. SOLUTION: In a state that mater shutoff valves 94 and 96 are shut off, the hydraulic pressure of brake cylinders 14 and 16 is controlled to a value higher than the hydraulic pressure of master cylinders. When the master shutoff valves 94 and 96 faultily fail to open, the high-pressure hydraulic fluid is returned from a hydraulic control cylinder 12 to the mater cylinder 10, and pressurizing pistons 36 and 38 are returned to retreat end positions. Flow-out of the hydraulic fluid from pressurization chambers 36 and 38 to a reservoir 54 is allowed, and the hydraulic pressure at a master cylinder side in relation to the flow-out hindrance valves 148 and 150 becomes high. The flow-out hindrance valves 148 and 150 are switched to the shutoff condition to hinder the flow-out of the hydraulic fluid from the pressurization chambers 36 and 38 to the reservoir 54. As a result, the control of the brake hydraulic pressure by the hydraulic control cylinder 12 can be continuously performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake device.

[0002]

2. Description of the Related Art JP-A-10-86804 discloses that
(a) a master cylinder that generates hydraulic pressure according to the operation state of the brake operating member, (b) a brake cylinder of a brake that is operated by hydraulic pressure, and (c) provided between the brake cylinder and the master cylinder. A master shut-off valve that can be switched between a shut-off state that shuts them off and a communication state that communicates with them, and (d) provided between the master shut-off valve and the brake cylinder, in the shut-off state of the master shut-off valve, A brake device including a brake fluid pressure control device that controls the fluid pressure of the brake cylinder based on the brake operation state is described. In this brake device, when the system is normal, the brake fluid pressure is controlled by the control of the brake fluid pressure control device with the master shut-off valve being in a shut-off state. When the system is abnormal, the master shut-off valve is switched to the communication state, and the brake is operated by supplying the hydraulic pressure of the master cylinder to the brake cylinder.

[0003]

However, in the above-described brake device, when the brake operation is abnormal, the brake fluid pressure control device does not control the brake fluid pressure. . Therefore, the present invention is to make it possible to control the brake fluid pressure using the brake fluid pressure control device even if the brake device is abnormal. The above object is attained by providing the brake device with the following configurations. Each mode is described in the same manner as in the claims, divided into sections, each section is numbered, and described in the form of citing the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the technology described in this specification, and the technical features and their combinations described in this specification should not be construed as being limited to the following sections. Absent. Further, when a plurality of items are described in one section, not all items must always be adopted together, but it is also possible to take out and adopt only some items. (1) a low-pressure source that stores hydraulic fluid at substantially atmospheric pressure, (a) a housing, and (b) a liquid-tight and slidably fitted to the housing and operated based on operation of a brake operating member; A pressurizing piston for generating a hydraulic pressure in the pressurizing chamber in front thereof in accordance with the operation state of the brake operating member; and (c) the low-pressure source from the pressurizing chamber in a state where the pressurizing piston is at the retreat end position. A master cylinder including an outflow control device that permits the flow of the hydraulic fluid to the outside and prevents the flow in the other state, and is provided between the master cylinder and the low-pressure source, and the hydraulic pressure of the pressurizing chamber is controlled by the brake. If the height is abnormal in relation to the operating state of the operating member, even if the outflow control device allows the outflow of the hydraulic fluid from the pressurizing chamber to the low-pressure source, the low-pressure source An outflow prevention device for preventing the outflow of hydraulic fluid to the Brake device according to symptoms (claim 1). In the brake device described in this section, the outflow control device is in the outflow allowable state in a state where the pressurizing piston is at the retreat end position, and the flow of the hydraulic fluid from the pressurizing chamber to the low pressure source is allowed. When the brake operation is released, the hydraulic fluid in the pressurized chamber can be returned to the low pressure source. However, when the hydraulic pressure in the pressurizing chamber is abnormally high in relation to the operation state of the brake operating member, the flow of the hydraulic fluid from the pressurizing chamber to the low pressure source is blocked. Even when the outflow control device enters the outflow allowable state, the flow of the hydraulic fluid from the pressurized chamber to the low-pressure source is blocked, and a decrease in the hydraulic pressure of the pressurized chamber can be suppressed. In addition to the master cylinder, the low pressure source, and the outflow prevention device described above, the brake device includes a master cylinder shut-off valve that can be switched between a brake cylinder and a shut-off state in which the brake cylinder is shut off from the master cylinder and a communication state in which the brake cylinder communicates with the master cylinder. And a brake fluid pressure control device that controls the fluid pressure of the brake cylinder when the master shut-off valve is shut off in many cases. In this case, for example, when the hydraulic pressure in the pressurized chamber becomes abnormally high due to an open failure of the master shut-off valve, the hydraulic fluid in the pressurized chamber is prevented from flowing out to the low-pressure source. The control of the brake fluid pressure by the brake fluid pressure control device can be continued. (2) a brake cylinder of a brake operated by hydraulic pressure, and a master shut-off valve provided between the brake cylinder and the pressurizing chamber and capable of switching between a shut-off state for shutting off the pressurized chamber and a communication state for communicating with the master. A brake fluid pressure control device that is provided between the master shut-off valve and the brake cylinder and that controls the hydraulic pressure of the brake cylinder based on the brake operation state when the master shut-off valve is shut off ( The brake device according to the item (1). The brake hydraulic pressure control device controls the hydraulic pressure of the brake cylinder when the master shut-off valve is shut off. The brake fluid pressure control device may control the brake fluid pressure using, for example, the fluid pressure of a power fluid pressure source. The brake fluid pressure control device includes one or more electromagnetic control valves. Or include a hydraulic control cylinder. The hydraulic pressure of the brake cylinder can be controlled by controlling the electromagnetic control valve or controlling the power supplied to the power drive source of the power hydraulic pressure source. (3) In the case where the outflow prevention device is to be controlled by the brake fluid pressure control device so that the fluid pressure of the brake cylinder is higher than the fluid pressure of the pressurizing chamber, the fluid pressure of the brake cylinder is increased. The brake device according to (2), further including an outflow prevention valve configured to prevent outflow of the hydraulic fluid from the pressurization chamber to the low-pressure source when the height is lower than a height determined based on the hydraulic pressure of the pressurization chamber of the master cylinder. (Claim 2).
"When the hydraulic pressure of the brake cylinder is lower than the height determined based on the hydraulic pressure of the pressurizing chamber of the master cylinder", "The hydraulic pressure of the pressurizing chamber of the master cylinder is higher than the height determined based on the hydraulic pressure of the brake cylinder." High ". When the hydraulic pressure of the brake cylinder is controlled to be higher than the hydraulic pressure of the master cylinder by the brake hydraulic pressure control device, the hydraulic pressure of the master shut-off valve on the brake cylinder side becomes higher than the hydraulic pressure on the master cylinder side. Therefore, when the hydraulic pressure of the brake cylinder is lower than the height determined based on the hydraulic pressure of the pressurizing chamber of the master cylinder, the master shut-off valve, which should be in the shut-off state, is in the communicating state, that is,
It can be considered that the master shut-off valve is abnormal (open failure). When the master shut-off valve has an open failure, high-pressure hydraulic fluid is supplied from the brake cylinder side of the master shut-off valve to the master cylinder side. The hydraulic pressure in the pressurizing chamber of the master cylinder may increase, and the hydraulic pressure in the pressurizing chamber may cause the pressurizing piston to retreat to the retreat end position. When the pressurizing piston is retracted to the retreat end position, the outflow control device allows the hydraulic fluid to flow out of the pressurizing chamber to the low-pressure source.
In the brake device according to the present mode, the outflow prevention valve prevents the hydraulic fluid from flowing out of the pressurizing chamber. Therefore, it is possible to prevent a decrease in the liquid pressure in the pressurizing chamber. In many cases, the hydraulic pressure of the brake cylinder is controlled by the brake hydraulic pressure control device based on the operating state of the brake operating member. In the pressurizing chamber of the master cylinder, a hydraulic pressure is generated according to the operation state of the brake operation member.
Therefore, while the master shut-off valve is in the shut-off state, a predetermined relationship should be established between the hydraulic pressure of the brake cylinder and the hydraulic pressure of the master cylinder. On the other hand, when the hydraulic pressure of the brake cylinder is lower than the height determined based on the hydraulic pressure of the pressurizing chamber of the master cylinder and the above-described predetermined relationship, for example, the hydraulic pressure of the brake cylinder is If it is lower than the value obtained by multiplying the hydraulic pressure of the chamber by the set value, the value obtained by subtracting the hydraulic pressure of the master cylinder from the hydraulic pressure of the brake cylinder is equal to or less than the set value determined based on the hydraulic pressure of the brake cylinder or the hydraulic pressure of the master cylinder. In some cases, when the brake operation state is equal to or higher than the set state and the value obtained by subtracting the master cylinder hydraulic pressure from the brake cylinder hydraulic pressure is equal to or lower than the set value, the master shut-off valve fails to open. The pressure in the pressure chamber can be considered abnormal. The outflow prevention valve may be a pilot-type cutoff valve that switches to a cutoff state due to this phenomenon, or may be an electromagnetic control valve that switches to a cutoff state in accordance with the supply current. In the case of an electromagnetic control valve, for example,
When the master shutoff valve is determined to have an open failure based on the master cylinder fluid pressure (master cylinder side of the master shutoff valve on the master cylinder side) and the brake cylinder fluid pressure (master shutoff valve on the brake cylinder side), the state is switched to the outflow prevention state. Will be. (4) In the case where the outflow prevention device is to be controlled by the brake hydraulic pressure control device so that the hydraulic pressure of the brake cylinder is higher than the hydraulic pressure of the pressurizing chamber, the pressure of the pressurizing chamber of the master cylinder is reduced. When the hydraulic pressure is higher than a height determined based on an operating force of the brake operating member and a predetermined relationship, an outflow prevention valve that prevents outflow of the hydraulic fluid from the pressurizing chamber to the low-pressure source is included. The brake device according to claim 2) or (3) (claim 3). The retreat end position of the pressurizing piston is often defined by a stopper or the like. In this case, the brake operating force and the reaction force of the stopper are applied to the pressurizing piston, and a hydraulic pressure corresponding to the sum of these is generated in the pressurizing chamber. On the other hand, when the position is other than the retreat end position, the reaction force of the stopper is not applied, so that a hydraulic pressure corresponding to the brake operating force is generated in the pressurizing chamber.
Therefore, when the brake operation force applied to the brake operation member is the same, the hydraulic pressure in the pressurizing chamber is higher at the retreat end position than at other positions. Then, an open failure of the master shutoff valve can be detected. (5) a brake cylinder of a brake operated by hydraulic pressure, and a master shut-off valve provided between the brake cylinder and the pressurizing chamber and capable of switching between a shut-off state for shutting off the pressurizing chamber and a communication state for communicating with the master. A brake fluid pressure control device that is provided between the master shut-off valve and the brake cylinder and controls the hydraulic pressure of the brake cylinder in the shut-off state of the master shut-off valve; The brake device according to (1), further including: a stroke simulator that allows a change in an operation stroke of the brake operation member and applies a reaction force according to an operation force. The brake fluid pressure control device described in this section,
The hydraulic pressure of the brake cylinder may be controlled based on the brake operation state, or may not be controlled based on the brake operation state. The stroke simulator may be connected between the pressurizing chamber and the master shut-off valve, or may be directly connected to the pressurizing chamber. In any case, according to the stroke simulator, when the master shut-off valve is in the shut-off state, the brake operating member can be operated with the same feeling as when the master shut-off valve is in the communicating state. (6) In the case where the outflow prevention device is to be controlled by the brake fluid pressure control device so that the brake fluid pressure is higher than the pressure chamber of the master cylinder, the fluid pressure in the pressure chamber is reduced by the brake operation. Including an outflow prevention valve for preventing the flow of the hydraulic fluid from the pressurizing chamber to the low-pressure source when the hydraulic pressure is higher than a hydraulic pressure determined based on the operation stroke of the member (5)
The brake device according to claim (claim 4). When the master shut-off valve is shut off and the stroke simulator communicates with the pressurizing chamber of the master cylinder,
A hydraulic pressure having a height corresponding to the operation stroke is generated.
On the other hand, when the master shut-off valve fails to open, the hydraulic pressure in the pressurizing chamber becomes higher than the hydraulic pressure determined based on the operation stroke. Therefore, based on the relationship between the operation stroke and the hydraulic pressure in the pressurizing chamber, it is possible to detect an open failure of the master shutoff valve. For example, when the hydraulic pressure of the pressurizing chamber is higher than a value obtained by multiplying the hydraulic pressure according to the operating stroke by a set value (the hydraulic pressure of the pressurizing chamber is determined based on the operating stroke rather than the hydraulic pressure according to the operating stroke). Higher than the set value). (7) The outflow prevention device can be switched between an outflow prevention state in which the outflow of the hydraulic fluid from the pressurizing chamber to the low pressure source is prevented and an outflow allowable state in which the outflow is allowed, in accordance with the supply current to the coil. The brake device according to any one of the above items (1) to (6), including a suitable electromagnetic control valve (claim 5). It is desirable that the electromagnetic control valve be a normally open valve that is open when no current is supplied. In normal braking, when the brake operation is released, the hydraulic fluid in the pressurizing chamber can be reliably returned to the low pressure source. (8) When the outflow prevention device controls the brake fluid pressure by the brake fluid pressure control device,
The master shut-off valve abnormality detecting unit for detecting that the master shut-off valve is abnormal, and when the master shut-off valve is detected as abnormal by the master shut-off valve abnormality detecting unit, the electromagnetic control valve flows out. (7) The brake device according to the above mode (7), including a flow-stop valve control unit that switches to a blocking state. The master shut-off valve abnormality detection unit may detect that the master shut-off valve is in the communication state although it should be in the shut-off state, that is, that the master shut-off valve is in the open failure state. As described above, the abnormality of the master shut-off valve is detected based on the hydraulic pressure of the master cylinder and the hydraulic pressure of the brake cylinder, based on the differential pressure across the master shut-off valve, It can be detected based on a brake operation state such as an operation force and an operation stroke and the hydraulic pressure of the master cylinder. (9) a low-pressure source that stores hydraulic fluid at substantially atmospheric pressure; (a) a housing; and (b) a pressure-tightly and slidably fitted housing that is operated based on the operation of a brake operating member. A master including a pressure piston, and (c) an outflow control device that allows the flow of the hydraulic fluid from the pressurization chamber to the low-pressure source when the pressure piston is at the retracted end position and blocks the flow in the other state. Cylinder, provided between the master cylinder and the low pressure source, the outflow control device, when the state of allowing the flow of the hydraulic fluid from the pressurized chamber to the low pressure source, the pressure chamber of the pressurized chamber A pilot member that includes a movable member that is operated in accordance with the hydraulic pressure and that prevents the hydraulic fluid from flowing out of the pressurizing chamber to a low-pressure source when the hydraulic pressure in the pressurizing chamber is equal to or higher than a predetermined set pressure. (6) A brake device comprising: In a state where the brake operating member is at the retreat end position, the outflow control device is in an outflow allowable state. The outflow of the hydraulic fluid from the pressurizing chamber to the low-pressure source is permitted. However, when the hydraulic fluid in the pressurizing chamber is allowed to flow out to the low-pressure source, and when the hydraulic pressure in the pressurizing chamber is equal to or higher than the set pressure, the movable member is moved and the outflow prevention valve communicates. The state is switched to the cutoff state. The outflow of the hydraulic fluid from the pressurizing chamber to the low-pressure source is prevented, and a decrease in the hydraulic pressure of the pressurizing chamber can be suppressed. Since the outflow prevention valve is a pilot valve, the outflow prevention valve can be switched to the cutoff state due to a failure of the electric system or the like. The pilot-type outflow prevention valve includes a movable member that is operated in a relationship between the hydraulic pressure of the pressurizing chamber and the hydraulic pressure of the brake cylinder. When the relationship becomes high, the outflow of the hydraulic fluid from the pressurizing chamber to the low-pressure source may be prevented. The brake device described in this section includes (1)
The technical features described in any of the items (8) to (8) can be adopted. (10) (i) a housing; (ii) a simulator piston which is fitted to the housing in a liquid-tight and slidable manner to partition the inside of the housing into two volume chambers; The first of one of the rooms
Biasing means disposed in a state of biasing in a direction to decrease the volume of the volume chamber, wherein the pressure chamber is connected to the first volume chamber, and the low-pressure source is connected to the other second volume chamber. A stroke simulator connected between the second volume chamber and the low-pressure source is provided between the second volume chamber and the low-pressure source, and a communication between the second volume chamber and the low-pressure source is established. Any one of the above items (1) to (9) including a simulator device including a simulator control valve that switches to a communication state.
The brake device according to claim 7 (claim 7). When the simulator control valve is in communication, the second volume chamber is connected to the low pressure source. A change in the volume of the first and second volume chambers is allowed, and the stroke simulator is brought into an operation allowable state.
When the simulator control valve is in the shut-off state, the second volume chamber is shut off from the low-pressure source, so that the volume change of the first and second volume chambers is prevented, and the operation of the stroke simulator is prevented. It is desirable that the simulator control valve be in the shut-off state when the master shut-off valve is in communication, and be in the communication state when the master shut-off valve is in the shut-off state. The simulator control valve may be switched between a communication state and a cutoff state based on a pilot pressure, or may be switched according to a supply current. In addition,
The simulator control valve may be provided between the first volume chamber and the pressurizing chamber of the master cylinder. (11) The simulator device includes a simulator control valve control unit that switches the simulator control valve to a shut-off state when an open failure occurs in the master shut-off valve. (10)
The brake device according to the paragraph. When the master shutoff valve fails to open, the pressurizing chamber is communicated with the brake cylinder, and there is no need to permit the operation of the stroke simulator. In this case, if the simulator control valve is switched to the shutoff state and the stroke simulator is switched to the operation inhibition state, wasteful consumption of the hydraulic fluid can be reduced. The simulator control valve can be switched to the shut-off state when the outflow prevention device is in the outflow prevention state or when the fluid pressure in the pressurizing chamber is abnormal. (12) The brake fluid pressure control device detects an operation force applied to the brake operation member by a driver by a driver, and at least the outflow prevention device is connected to the low pressure source from the pressurizing chamber to the low pressure source. An operating force-responsive brake fluid pressure control unit that controls the brake fluid pressure based on the brake operating force detected by the operating force detecting unit when in the outflow blocking state that blocks the flow of the hydraulic fluid (2 (8) The brake device according to any one of (8), (10) and (11) (claim 8). As described above, the relationship between the operating force of the brake operating member and the hydraulic pressure of the pressurizing chamber of the master cylinder differs between when the outflow prevention device is in the outflow prevention state and when it is in the outflow allowable state. In the outflow prevention state of these two states, it is necessary to consider the reaction force of the stopper and the like. Therefore, in the brake device described in this section, at least in the outflow prevention state, the brake hydraulic pressure is controlled based on the operating force, not the hydraulic pressure of the pressurizing chamber. When the outflow prevention device is in the outflow allowable state, it may be controlled based on the operating force or may be controlled based on the hydraulic pressure of the pressurizing chamber. In addition, the brake fluid pressure control unit corresponding to the operating force may be considered to control the brake fluid pressure based on the operating force when the master shut-off valve has an open failure. (13) a low-pressure source that stores hydraulic fluid at substantially atmospheric pressure, (a) a housing, and (b) a liquid-tight and slidably fitted to the housing and operated based on operation of a brake operating member; A pressurizing piston for generating a hydraulic pressure in the pressurizing chamber in front thereof in accordance with the operation state of the brake operating member, (c)
A master cylinder including an outflow control device that allows the flow of the hydraulic fluid from the pressurizing chamber to the low-pressure source in a state where the pressurizing piston is at the retracted end position, and blocks the flow in the other state; A brake cylinder for the brake to be operated, a master shutoff valve provided between the brake cylinder and the pressurizing chamber and capable of switching between a shutoff state for shutting off the pressurized chamber and a communication state for communicating with the brake cylinder, the master shutoff valve, A brake fluid pressure control device provided between the master cylinder and a low pressure source, the brake fluid pressure control device being provided between the master cylinder and a low pressure source when the master shut-off valve is in a shut-off state, and controlling a hydraulic pressure of the brake cylinder; Even when the outflow control device allows the flow of the hydraulic fluid from the pressurized chamber to the low-pressure source at the time of the valve opening failure, the flow of the hydraulic fluid from the pressurized chamber to the low-pressure source is prevented. Brake system which comprises an outflow preventing device for stopping. The technical features described in any of the above modes (1) to (12) can be employed in the brake device described in this mode. (14) a low-pressure source that stores hydraulic fluid at substantially atmospheric pressure, (a) a housing, and (b) a liquid-tight and slidably fitted to the housing and operated based on an operation of a brake operating member; A pressurizing piston for generating a hydraulic pressure in the pressurizing chamber in front thereof in accordance with the operation state of the brake operating member, (c)
A master cylinder including an outflow control device that allows the flow of the hydraulic fluid from the pressurizing chamber to the low-pressure source in a state where the pressurizing piston is at the retreat end position, and blocks the flow in the other state; The relationship between the hydraulic pressure of the pressurizing chamber of the master cylinder and the operation state of the brake operating member is provided between the low-pressure source and the hydraulic pressure of the pressurizing chamber for the same operating state. In this case, even if the outflow control device allows the flow of the hydraulic fluid from the pressurized chamber to the low-pressure source, the outflow control device may block the flow of the hydraulic fluid from the pressurized chamber to the low-pressure source. A brake device characterized by including.
The technical features described in any of the above modes (1) to (13) can be adopted in the brake device described in this mode. (15) a low-pressure source that stores hydraulic fluid at approximately atmospheric pressure, (a) a housing, and (b) a liquid-tight and slidably fitted to the housing and operated based on an operation of a brake operating member; A pressurizing piston for generating a hydraulic pressure in the pressurizing chamber in front thereof in accordance with the operation state of the brake operating member, (c)
A master cylinder including an outflow control device that allows the flow of the hydraulic fluid from the pressurizing chamber to the low-pressure source in a state where the pressurizing piston is at the retracted end position, and blocks the flow in the other state; A brake cylinder for the brake to be operated, a master shutoff valve provided between the brake cylinder and the pressurizing chamber and capable of switching between a shutoff state for shutting off the pressurized chamber and a communication state for communicating with the brake cylinder, the master shutoff valve, A brake fluid pressure control device provided between the brake cylinder and the master shutoff valve for controlling the hydraulic pressure of the brake cylinder based on the brake operation state in a shutoff state of the master shutoff valve; and the master shutoff valve may be abnormal. A master shut-off valve abnormality possibility detecting unit for detecting the oil pressure, provided between the master cylinder and the low pressure source, When it is detected that there is a possibility that the master shut-off valve is abnormal, even if the outflow control device is allowed to flow the hydraulic fluid from the pressurized chamber to the low-pressure source, A brake device (10) for stopping the flow of the hydraulic fluid to the low-pressure source. It is desirable that the outflow prevention device includes an electromagnetic control valve that can be switched between a communication state and a cutoff state according to a supply current. The outflow prevention device is configured to prevent the flow of the hydraulic fluid when the master shutoff valve abnormality possibility detection unit detects that there is a possibility that the operation fluid is abnormal.
If the possibility is higher than the set degree, it may be blocked. For the brake device described in this section,
The technical features described in any of (14) can be adopted.

[0004]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a brake device according to an embodiment of the present invention will be described in detail with reference to the drawings.
Reference numeral 10 denotes a master cylinder, and reference numeral 12 denotes a hydraulic pressure cylinder as a brake hydraulic pressure control device. Also, 14,1
6 is a brake 2 for suppressing rotation of the front wheel 18 and the rear wheel 20.
2, 24 brake cylinders. The brake cylinders 14 and 16 are connected to the master cylinder 10 via the hydraulic control cylinder 12.

The master cylinder 10 comprises two pressurizing pistons 3 provided in a housing 28 in a liquid-tight and slidable manner.
0, 32, and the pressurizing piston 30 is linked to a brake pedal 34 as a brake operating member.
The pressurizing chamber 36 in front of the pressurizing piston 32 is connected to the brake cylinder 14 of the front wheel 18, and the pressurizing chamber 38 in front of the pressurizing piston 30 is connected to the brake cylinder 16 of the rear wheel 20. The same pressure is generated in the two pressure chambers 36 and 38. The pressurizing piston 30 has a stepped shape, and the pressurizing chamber 3 is formed in the small diameter portion 42.
8. An annular chamber 46 is formed by the step portion of the large diameter portion 44 and the small diameter portion 42 and the housing 28.
A communication path 48 for communicating the annular chamber 46 and the pressurizing chamber 38 is provided in the small-diameter portion 42.
A check valve 50 is provided to allow the flow of the working fluid from 6 to the pressurizing chamber 38 and prevent the flow in the opposite direction.

[0006] A reservoir 54 is connected to the annular chamber 46 via a flow restricting device 52. The working fluid is stored in the reservoir 54 at substantially atmospheric pressure. Distribution restriction device 52
Is a check valve 55 that allows the flow of hydraulic fluid in the direction from the reservoir 54 to the annular chamber 46 and prevents the flow in the opposite direction.
And a relief valve 56 that allows the flow of the hydraulic fluid from the annular chamber 46 to the reservoir 54 when the hydraulic pressure of the annular chamber 46 is higher than the hydraulic pressure of the reservoir 54 by a set pressure (relief pressure) or more.
Orifices 57 are provided in parallel with each other.

As the pressure piston 30 advances (leftward in the figure), the hydraulic pressure in the annular chamber 46 and the pressure chamber 38 is increased.
The hydraulic pressure in the annular chamber 46 is increased until the relief pressure of the relief valve 68 is reached. The hydraulic pressure in the annular chamber 46 is
Is higher than the hydraulic pressure of the check valve 50
Is supplied to the pressurizing chamber 38 and supplied to the brake cylinder 16. In the present embodiment, the relief pressure is set to a height at which the first fill is almost completed. Until the first fill is completed, the hydraulic fluid is supplied to the annular chamber 4.
6 and the pressurizing chamber 38 are supplied to the brake cylinder 16, so that the first fill can be completed quickly. When the hydraulic pressure in the annular chamber 46 reaches the relief pressure, the hydraulic fluid flows through the relief valve 56 to the reservoir 54.
Spilled to. In this state, although the hydraulic pressure in the pressurizing chamber 38 is higher than the hydraulic pressure in the annular chamber 46, the check valve 5
0 prevents the working fluid in the pressurized chamber 38 from flowing into the annular chamber 46. The hydraulic fluid is supplied to the brake cylinders 14 and 16 from the pressurizing chambers 36 and 38 and the hydraulic fluid is not supplied from the annular chamber 46. Thus, the flow restricting device 52 can be referred to as a fill-up device.

Thereafter, the hydraulic pressure in the pressurizing chamber 38 is increased as the pressurizing piston 30 advances. In this case, since the liquid pressure in the pressurizing chamber 38 is pressurized by the small diameter portion 42,
As compared with the case where the large-diameter portion 44 is pressurized (the hydraulic pressure of both the annular chamber 46 and the pressurized chamber 38 is pressurized), the brake pedal 3
The hydraulic pressure in the pressurizing chamber 38 in the case where the operating force of 4 is the same is increased. The boost factor increases. Since the annular chamber 46 and the reservoir 54 are connected via the orifice 57, when the pressurizing piston 30 is in a steady state, the hydraulic pressure in the annular chamber 46 is substantially at atmospheric pressure. When the pressurizing piston 32 is retracted, the volume of the annular chamber 46 is increased. However, as the volume of the annular chamber 46 increases, the hydraulic fluid is supplied from the reservoir 54 via the check valve 55. Therefore, the negative pressure in the annular chamber 46 is avoided.

When the cross-sectional area (pressure receiving area) of the large-diameter portion 44 is Am1 and the cross-sectional area of the small-diameter portion 42 is Am3, the movement of the pressurizing piston 30 when the brake cylinder 16 and the master cylinder 10 are in communication with each other. When the stroke is ΔL, the hydraulic fluid amount q flowing out of the pressurizing chamber 38 is (Am1 · ΔL) before the end of the first fill, and (Am3 · ΔL) after the end of the first fill. (A
m1> Am3). Further, when the increase amount of the hydraulic pressure corresponding to the increase amount of the pedaling force is ΔPF, the hydraulic pressure of the pressurizing chamber 38 becomes
Before the first fill is completed, the increasing gradient ΔPM (=
.DELTA.PF, whereas after the first fill, the increasing gradient .DELTA.PM (= .DELTA.PF.Am1 / Am).
Increased in 3). As described above, before the first fill is completed, the hydraulic fluid can be supplied to the brake cylinder at a large flow rate, and after the first fill has been completed, the hydraulic pressure can be increased with a large pressure increase gradient.

A pair of cup seals 60, 6 are provided in portions of the housing 28 corresponding to the pressure chambers 36, 38, respectively.
1 is provided. In addition, these cup seals 60,
Ports 63 and 64 are provided between the cylinders 61, respectively, and liquid passages 66 and 67 extending from the reservoir 54 are connected to each other. Communication passages 69 and 70 are formed in the pressurizing pistons 32 and 30, respectively.
The pressurizing chambers 36 and 38 are communicated with the reservoir 54 with the pressurizing chambers 3 and 9 facing the ports 63 and 64, respectively.
The flow of hydraulic fluid from 6, 38 to the reservoir 54 is allowed. The position where the flow of the hydraulic fluid from the pressurizing chambers 36 and 38 to the reservoir 54 is allowed, that is, the position where the communication passages 69 and 70 and the ports 63 and 64 face each other is the retreat end position.
The retracted end position of the pressure piston 30 is defined by a stopper 71. Also, return springs 73 and 74 are provided between the bottom of the housing 28 and the pressure piston 32 and between the pressure pistons 30 and 32, respectively.
Thereby, the retreat end position of the pressurizing piston 32 is determined. In the present embodiment, the outflow control device 75 is configured by the ports 63 and 64, the communication passages 69 and 70, and the like.
The state in which these oppose each other is the outflow permission state, and the other state is the outflow prevention state.

The hydraulic pressure control cylinder 12 is connected to the pressurizing chamber 36 by a liquid passage 76. A stroke simulator 78 is provided in the middle of the liquid passage 76. The stroke simulator 78 is slidably provided in the housing and divides the interior of the housing into two chambers. A spring 82 urges the simulator piston 80 in a direction in which the volume of one of the chambers decreases. including. The above-described pressurizing chamber 36 is connected to the first volume chamber 86 on one side of the simulator piston 80, and the hydraulic pressure control cylinder 12 is connected to the other second volume chamber 88. The aforementioned spring 82 is provided in the second volume chamber 88,
The first volume chamber 86 is provided in a reduced state. The volume of the first volume chamber 86 is changed in accordance with the operation of the brake pedal 34, the spring 82 is elastically deformed accordingly, and a corresponding reaction force is applied to the brake pedal 34.

The brake cylinder 14 of the front wheel 18 is connected to the pressurizing chamber 36 by a liquid passage 90, and the brake cylinder 1 of the rear wheel 20 is connected to the pressurizing chamber 38 by a liquid passage 92.
6 is connected. In the middle of the liquid passages 90 and 92, master shut-off valves 94 and 96, which are electromagnetic on-off valves, are provided, respectively. The opening and closing of the master shutoff valves 94 and 96 causes the brake cylinders 14 and 16 to communicate with the master cylinder 10 or to shut off. Master shut-off valve 94, 9
Reference numeral 6 denotes a normally-open valve that is open when no current is supplied.

In the present embodiment, the master shutoff valves 94 and 96 are switched from the open state to the closed state when the first fill is completed while the electric system is normal. The hydraulic fluid is supplied to the brake cylinders 14 and 16 from the master cylinder 10 at the beginning of the brake operation, and then supplied from the hydraulic pressure control cylinder 12. Further, when the electric system is abnormal or the like, the state is switched to the open state, and the hydraulic fluid of the master cylinder 10 is supplied to the brake cylinders 14 and 16 so that the brakes 22 and 2 are opened.
4 is activated. Check valves 98 are provided in parallel with the master shutoff valves 94 and 96, respectively. The check valve 98 allows the flow of the hydraulic fluid from the master cylinder side to the brake cylinder side and prevents the flow in the reverse direction. According to the check valve 98, when the master shut-off valves 94 and 96 are closed, the hydraulic pressure of the master cylinder 10 increases.
When the hydraulic pressure becomes higher than the hydraulic pressures of the cylinders 4 and 16, the hydraulic fluid can be supplied from the master cylinder 10 to the brake cylinders 14 and 16.

The master shut-off valves 94, 9 of the liquid passages 90, 92
A hydraulic control cylinder 12 is provided downstream of 6. The hydraulic control cylinder 12 is provided with an electric control motor 10.
It is activated based on the activation of 0. Control motor 10
0 is operable in both forward and reverse directions, and the rotational motion of the control motor 100 is converted by the motion converting device 102 into linear motion. The hydraulic control cylinder 12 includes control pistons 106 and 108 provided in the housing 104 in a liquid-tight and slidable manner. An O-ring 109 is provided on the outer periphery of the control piston 106, and is kept liquid-tight. The control piston 106 is moved with the movement of a drive shaft 110 as an output shaft of the motion conversion device 102. The control piston 106 is moved forward and backward by the operation of the control motor 100. As shown in the figure, the rotation of the output shaft 111 of the electric motor 100 is controlled by a pair of gears 11.
2, 114 to the rotating shaft 116,
The rotation of 16 is converted into linear motion by the motion conversion device 102 and output to the drive shaft 110. In the present embodiment, the motion conversion device 102 has a ball screw mechanism.

The brake cylinders 14 and 16 of the front wheel 18 and the rear wheel 20 are connected to control pressure chambers 120 and 122 in front of the control pistons 106 and 108 (rightward in the figure). The master cylinder 10 and the brake cylinders 14 and 16 are connected via the control pressure chambers 120 and 122.

The control pistons 106 and 108 are arranged concentrically and in series with each other. Also, return springs 124 and 126 are provided between the two control pistons 106 and 108 and between the control piston 108 and the housing 104.
Is provided. The control piston 108 is connected to the control pressure chamber 1
The control piston 108 can be referred to as a floating piston in this sense. Also, the control piston 108
The pressure receiving surfaces facing the control pressure chambers 120 and 122 have the same area, and the return springs 124 and 126 have substantially the same urging force. Therefore, the hydraulic pressures of the control pressure chambers 120 and 122 are set to the same height. The hydraulic fluid of the same height is supplied to the brake cylinders 14 and 16 of the front wheel 18 and the rear wheel 20, respectively.
The hydraulic pressure of 16 is increased / decreased in common by the control of the hydraulic pressure control cylinder 12. Control piston 1
08 is slidably fitted to the housing 104 through a seal member 127 in a liquid-tight manner.
Thus, the control pressure chambers 120 and 122 are isolated, and the two systems are independent. Note that the seal member 127 may be provided on the control piston side.

The reservoir 54 is connected to the rear chamber 128 behind (to the left in the figure) the control piston 106 by a reservoir passage 130, and the reservoir passage 130 is provided with an electromagnetic on-off valve 132. The solenoid on-off valve 132 is a normally closed valve in a closed state while no current is supplied, and is closed when the master shutoff valves 94 and 96 are in a communicating state, and the master shutoff valves 94 and 96 are in a shutoff state. In this case, it is opened. When the electromagnetic on-off valve 132 is in the open state, a change in the volume of the second volume chamber 88 of the stroke simulator 78 is allowed.
Is in the operation permitting state, but when it is closed, the change in the volume of the second volume chamber 88 is prevented, so that the operation of the stroke simulator 78 is prevented. The solenoid on-off valve 132 is
It can be considered as a switching enable / disable device for switching the stroke simulator 78 between the operation permission state and the operation inhibition state.

The control piston 106 is connected to the control motor 10
As the control piston 106 advances, the volume of the rear chamber 128 increases. The rear chamber 128 includes the second volume chamber 8 as described above.
8 or the working fluid is supplied from the reservoir 54. The liquid pressure in the rear chamber 128 becomes atmospheric pressure. The control piston 10
6, a driving force corresponding to the driving torque of the control motor 100 is applied. The hydraulic pressure of the control pressure chambers 120 and 122 is controlled to a height corresponding to the driving force applied to the control piston 106. . The driving force, that is, the current supplied to the control motor 100 is controlled so that the hydraulic pressure in the control pressure chambers 120 and 122 approaches a target brake hydraulic pressure described later. Further, reference numeral 144 in the figure denotes a thrust bearing.
46 is a radial bearing. These receive axial and radial forces. Further, an axial force from the control pressure chamber side is received by the flange 148.

The liquid passages 66 and 67 connecting the master cylinder 10 and the reservoir 54 are provided with pilot type outflow prevention valves 148 and 150 shown in FIG. 6, respectively. The outflow prevention valve 148 is fitted to the housing 151 and the housing 151 in a liquid-tight and slidable manner, and is operated based on the hydraulic pressure in the pressurizing chamber 36 in a state where the pressurizing piston 32 is at the retracted end position. And a member 152. The valve member 152 has a generally stepped shape having a large diameter portion 153 and a small diameter portion 154. Housing 151
The large-diameter portion of the valve member 152 has a master cylinder-side port 155, and the small-diameter portion has a reservoir port 156 as a valve seat. A port 157 is also formed in an intermediate portion of the housing 151, and a liquid passage 158 connected to the master cylinder side of the liquid passage 66 is connected. An orifice 159 is provided in the liquid passage 158. Further, a spring 160 is provided between the valve member 152 and the housing 151 so that the valve member 152 can be connected to the valve seat 15.
6 is urged away from 6.

When the outflow control device 75 is in the outflow permitting state and the outflow prevention valve 148 is at the original position shown in the drawing, the valve member 152 is in a communicating state in which it is separated from the valve seat 156. An annular chamber 161 formed by the step portion of the valve member 152 and the housing 151 communicates with the reservoir 54. The pressurizing chamber 36 and the reservoir 54 are communicated with each other, and the hydraulic fluid in the pressurizing chamber 36 is supplied to the liquid passage 66 (liquid passage 158), the annular chamber 161, and the reservoir-side port 156.
Through the reservoir 54.

When the hydraulic pressure of the hydraulic fluid supplied to the master cylinder side port 155 becomes equal to or higher than the set pressure, the valve member 152 is advanced, and the tip 162 of the small diameter portion 154 is moved to the valve seat 15.
6 to be cut off. The tip 162 is a valve. Since the orifice 159 is provided in the liquid passage 158, when the hydraulic fluid is supplied from the pressurizing chamber 36 at a large flow rate, the hydraulic pressure in the annular chamber 161 and the hydraulic pressure in the master cylinder side port 155 are reduced. Difference occurs, and the valve member 152
The hydraulic pressure in the pressurizing chamber 36 acts on. When the area S1 of the pressure receiving surface of the large diameter portion 153 of the valve member 152 and the urging force f of the spring 160 are set, the hydraulic pressure P of the hydraulic fluid supplied to the master cylinder side port 155 satisfies the expression P> f / S1. In this case, the outflow prevention valve 148 is switched to the shut-off state.

In the shut-off state, the liquid passage 158
The hydraulic fluid in the pressurizing chamber 36 is also supplied to the annular chamber 161 via the hydraulic chamber 161.
Becomes equal to the hydraulic pressure. The hydraulic pressure in the annular chamber 161 is
The area acting on 52 is (S1−S2), and the cutoff state is maintained while the equation P · S1> P · (S1−S2) + f holds, that is, the equation P> f / S2 holds. The area S2 is such that the valve element 162 is seated on the valve seat 156 so that the annular chamber 16
1 (area of a portion inside the portion where the valve element 162 contacts the valve seat 156). As described above, even when the outflow control device 75 enters the outflow allowable state, when the hydraulic pressure in the pressurizing chamber 36 becomes equal to or higher than the set pressure, the outflow prevention valve 148 is switched to the shutoff state, and The outflow of the hydraulic fluid to the reservoir 54 is prevented.

On the other hand, when the hydraulic fluid is returned from the master cylinder 10 to the reservoir 54 in a state where the normal brake operation is released and the pressurizing pistons 30 and 32 are returned to the retracted end positions, the outflow occurs. The blocking valve 148 is kept in communication. The outflow prevention valve 148 is not switched to the shut-off state by the applied hydraulic pressure P 'generated when the brake operation is released, and the expression P'<f / S1 is satisfied. In the present embodiment,
The urging force f of the spring 160 and the structure of the outflow prevention valve 148 are designed so that the following equation is satisfied. P.S2>f>P'.S1 Note that the shutoff valve 150 has the same structure as the outflow prevention valve 148, and a description thereof will be omitted.

Downstream of the fluid pressure control cylinder 12 in the fluid passages 90 and 92, fluid pressure control valve devices 166 and 166 are provided, respectively.
168 are provided. Hydraulic pressure control valve devices 166, 16
8 each include a holding valve 170 and a pressure reducing valve 172. The holding valve 170 is provided between the hydraulic control cylinder 12 and the brake cylinders 14 and 16, and the pressure reducing valve 172 is
The brake cylinder 14.16 of each wheel 18, 20 is provided between the brake cylinders 14, 16 and the reservoir 174 by controlling the holding valve 170 and the pressure reducing valve 172.
Are separately controlled. In the present embodiment, each wheel 1 is controlled by the hydraulic pressure control valve devices 166 and 168.
Anti-lock control is performed so that the braking slip states of 8, 20 are appropriate for the friction coefficient of the road surface. A pump passage 180 extends from the reservoir 174 and is connected upstream of the holding valve 170 and downstream of the hydraulic control cylinder 12. Pump passage 180
, A pump 182, check valves 184, 186 and a damper 188 are provided. The pump 182 is operated by driving a pump motor 190.

The present brake device uses a brake E shown in FIG.
It is controlled by the CU 200. Brake ECU 200
Includes a control unit 202 mainly composed of a computer and a plurality of drive circuits. The control unit 202 includes a CPU 204, an RO
M206, RAM 208, input / output unit 210, and the like.
The input / output unit 210 includes a brake switch 21 for detecting whether or not the brake pedal 34 is depressed.
1. A treading force sensor 212 that detects a treading force applied to the brake pedal 34, a master pressure sensor 214 that detects a fluid pressure in the pressurizing chamber 38 of the master cylinder 10, and a fluid pressure in the control pressure chamber 120 of the fluid pressure control cylinder 12. Control pressure sensor 2
16, a wheel speed sensor 218 for detecting the rotation speed of each wheel 18, 20 and the like are connected. Master pressure sensor 212
Is provided in a liquid passage 92 connected to the pressurizing chamber 38. The control pressure sensor 216 detects the hydraulic pressure of the control pressure chambers 120 and 122, but detects the hydraulic pressure of the brake cylinders 14 and 16 while the hydraulic pressure control devices 166 and 168 are at the original positions shown in the figure.

The input / output unit 210 includes a driving circuit 2
26, coils such as a holding valve 170, a pressure reducing valve 172, master shutoff valves 94 and 96, and an electromagnetic opening / closing valve 132 are connected, and a pump motor 190, a control motor 10
0 etc. are connected. Further, the ROM 206 stores a normal brake control program represented by the flowchart of FIG. 3, various programs such as an antilock control program (not shown in the flowchart), and a target brake fluid pressure determination table shown in FIGS. Is stored.

Next, the operation will be described. In the normal state, no current is supplied to the coil of each solenoid control valve,
It is in the original position shown. When the brake pedal 34 is operated, the pressurizing pistons 30 and 32 are advanced accordingly, and the brake cylinders 14 and 1 are moved from the pressurizing chambers 36 and 38.
Hydraulic fluid is supplied to 8, and the brakes 22, 24 are operated. When the brake fluid pressure reaches the fluid pressure at the time when the first fill is completed, the master shutoff valves 94 and 96 are switched to the shutoff state. With the brake cylinders 14 and 16 disconnected from the master cylinder 10, the hydraulic pressure of the brake cylinders 14 and 16 (hereinafter simply referred to as brake hydraulic pressure) is controlled by the control of the hydraulic pressure control cylinder 12.
In this case, the solenoid on-off valve 132 is opened. The change in the volume of the second volume chamber 88 is allowed, and the stroke simulator 78 is in the operation permission state. When the brake pedal 34 is depressed, the hydraulic fluid in the pressurizing chamber 36 is supplied to the stroke simulator 78, and a corresponding reaction force is applied to the brake pedal 34. First volume chamber 86
Is increased, the volume of the second volume chamber 88 is reduced.

The hydraulic pressure control cylinder 12 is controlled based on the operation state of the brake pedal 34. A target value (for example, target brake fluid pressure, target deceleration) is determined based on the brake operation state, and control is performed so that an actual detection value (for example, actual brake fluid pressure, actual front-rear G) approaches the target value. . In the present embodiment, the target brake fluid pressure is determined based on the master cylinder pressure detected by the master pressure sensor 214, assuming that the master cylinder pressure is a value corresponding to the depression force of the brake pedal 34, and the actual brake fluid pressure is determined. Control motor 10 so as to approach the target brake fluid pressure.
The supply current to zero is controlled. On the other hand, when the open failure of the master shutoff valves 94 and 96 is detected, the control is performed based on the pedaling force detected by the pedaling force sensor 212.

In this embodiment, the master shutoff valve 9
In the shutoff state of 4,96, as shown in FIG. 4, the target brake hydraulic pressure PB is determined to be higher than the hydraulic pressure PMC of the pressurizing chambers 36,38. The ratio γ of the target brake fluid pressure PB to the master cylinder fluid pressure is set to a value larger than 1. As a result, master shut-off valves 94, 96
When the hydraulic pressure of the brake cylinders 14 and 16 is controlled by the control of the hydraulic pressure control cylinder 12 in the shut-off state, the hydraulic pressure of the master shut-off valves 94 and 96 on the brake cylinder side is higher than the hydraulic pressure on the master cylinder side. Will be expensive. When the master shut-off valves 94 and 96 are open failure, the target brake fluid pressure is determined based on the pedaling force as shown in FIG.

When the master shut-off valves 94 and 96 open and fail, the hydraulic pressure of the hydraulic pressure control cylinder 12 becomes lower than the master shut-off valve 9.
After returning to the pressurizing chambers 36 and 38 via 4,96. As a result, the hydraulic pressures in the pressurizing chambers 36 and 38 increase, and the pressurizing pistons 30 and 32 return to the retracted end positions, and the outflow control device 75 switches to the outflow allowable state. The outflow of the working fluid from the pressurizing chambers 36 and 38 toward the reservoir 54 is allowed. In this state, when the hydraulic pressure of the hydraulic fluid supplied to the master cylinder side port 155 of the outflow prevention valves 148, 150 becomes equal to or higher than the set pressure, the outflow prevention valves 148, 150 are switched to the shutoff state.

The brake operating force is applied when the pressure piston 30 is at the retreat end position, but the pressure piston 30 is in contact with the stopper 71. Therefore, both the brake operating force and the reaction force of the stopper 71 are applied to the pressurizing piston 30, and the pressurizing chambers 36 and 38 are applied.
, A hydraulic pressure corresponding to both of them is generated. On the other hand, when it is located at a position other than the retreat end position, no reaction force is applied by the stopper 71, so that a hydraulic pressure corresponding to the operation force is generated. Therefore, when the vehicle is at the retreat end position, the brake fluid pressure is controlled based on the treading force detected by the treading force sensor 212 instead of the master pressure.

The fact that the master shutoff valves 94 and 96 are not in the closed state, that is, in the open failure state, is detected based on the hydraulic pressure detected by the master pressure sensor 214 and the hydraulic pressure detected by the control pressure sensor 216. Can be. In the present embodiment, when the hydraulic pressure detected by the control pressure sensor 216 is smaller than the brake hydraulic pressure (a value obtained by multiplying the detected master pressure by a set value) determined based on the master pressure detected by the master pressure sensor 214, the master is shut off. The valves 94, 96 are said to be in an open fault.

In the flowchart of FIG. 3, in step 1 (hereinafter abbreviated as S1; the same applies to other steps), it is determined whether or not the brake pedal 34 is depressed. When it is depressed, in S2, it is determined whether or not the hydraulic pressure detected by the control pressure sensor 216 has reached the hydraulic pressure at the end of the first fill. Before reaching the first fill end hydraulic pressure, in S3, the master shutoff valves 94 and 96 and the electromagnetic on-off valve 132 are maintained at the original positions shown in the figure. The master shut-off valves 94 and 96 remain open, and the electromagnetic shut-off valves 132
Remains closed. Since the hydraulic fluid is supplied to the brake cylinders 14 and 16 at a large flow rate, the first fill can be quickly completed. Further, since the electromagnetic on-off valve 132 is in the closed state, the stroke simulator 78 is also in the operation inhibition state. The supply of the working fluid in the pressurizing chamber 36 to the stroke simulator 78 is avoided, and the working fluid can be effectively supplied to the brake cylinders 14 and 16.

When the first fill is completed, the master shutoff valves 94 and 96 are closed in S4, and the electromagnetic on-off valve 132 is switched to the open state. In S5, the master pressure and the control pressure are read, and the master shutoff valves 94 and 9 are read.
It is determined whether 6 is normal (closed) or an open fault. If the value obtained by subtracting the master pressure from the control pressure is equal to or greater than the set value, it is determined that the vehicle is in the closed state, and in S6, the target brake fluid pressure is determined based on the master pressure.
In S7, the current supplied to the control motor 100 is controlled such that the actual brake fluid pressure approaches the target brake fluid pressure. When the master shut-off valves 94 and 96 are in the open failure state, that is, in the open state when they should be closed, in step S8, the pedaling force is read, and the target brake fluid pressure is determined based on the pedaling force. .

On the other hand, when the brake switch 211 is in the OFF state, in S3, the master shut-off valves 94 and 96 are returned to the original positions shown in FIG. Will be returned. It is desirable, but not essential, that the solenoid on-off valve 132 be kept open for the time necessary to reliably return the hydraulic fluid in the rear chamber 128 and then returned to the closed state. The hydraulic fluid in the rear chamber 128 is the second fluid of the stroke simulator 78.
Since the hydraulic fluid is returned to the volume chamber 88, the hydraulic fluid in the first volume chamber 86 can be reliably returned to the master cylinder 10.

As described above, in the present embodiment, when an open failure occurs in the master shutoff valves 94 and 96, the outflow prevention valve 1
Since the valves 48 and 150 are in the cutoff state, the control of the brake fluid pressure by the control of the fluid pressure control cylinder 12 can be continuously performed. Further, when the pressurizing piston 30 is at the retreat end position, the brake fluid pressure is controlled based on the pedaling force, so that the brake fluid desired by the driver is compared with the case where the brake fluid pressure is controlled based on the master pressure. Pressure can be obtained.

The outflow prevention valve may have a structure shown in FIG. In FIG. 7, the outflow prevention valve 250
The housing 252, like the outflow prevention valve 148,
And a valve member 254 fitted to the housing 252 in a liquid-tight and slidable manner. The valve member 254 includes an outflow prevention valve 148.
Similarly to the above, a stepped shape having a large diameter portion 256 and a small diameter portion 258 is formed. Further, a stepped fitting hole 264 having a large diameter portion 260 and a small diameter portion 262 is formed in the housing 252.
The large diameter portion 256 of the valve member 254 is fitted to the large diameter portion 260, and the small diameter portion 258 of the valve member 254 is fitted to the small diameter portion 262.

The housing 252 has an outflow prevention valve 148.
Similarly, a master cylinder port 155 and a reservoir port 156 as a valve seat are formed, and a port 265 is provided at an intermediate portion of the small diameter portion 262 and an intermediate portion of the large diameter portion 260 of the fitting hole 264, respectively. , 266 are formed. A liquid passage 272 connected to the master cylinder side of the liquid passage 66 is connected to the small diameter side annular chamber 270, and a liquid passage 276 connected to the reservoir side of the liquid passage 66 is connected to the large diameter side annular chamber 274. It is connected. An orifice 278 is provided in the liquid passage 272. A spring 280 is provided between the housing 252 of the large-diameter portion-side annular chamber 274 and the valve member 254 to urge the valve member 254 in a direction to separate the valve member 254 from the valve seat 156.

In the original position shown, the valve member 254
Is separated from the valve seat 156, and the outflow prevention valve 25
0 is in a communication state. On the other hand, when the hydraulic pressure P of the hydraulic fluid supplied to the master cylinder side port 155 becomes larger than the set value, the valve member 254 is advanced, and the small diameter portion 2 is moved.
The distal end portion 282 of the valve 58 contacts the valve seat 156 to be shut off. Then, the cutoff state is maintained. In the present embodiment, the urging force f of the spring 280 and the structure of the outflow prevention valve 250 are formed so as to satisfy the expression P ・ (S1−S2 + S3)>f> P′ＰS1. Here, S1, S2, S3
Indicates the pressure receiving area of the large-diameter portion 256 of the valve member 254, the cross-sectional area of the small-diameter portion 258, and the area inside the portion of the valve element 282 that contacts the valve seat 156, respectively. Outflow prevention valve 250
In this case, since the area where the master cylinder hydraulic pressure acts in the shut-off state becomes larger than the outflow prevention valve 148,
The degree of freedom in designing the biasing force of the spring 280 can be increased.

It should be noted that an open failure does not always occur in both master shut-off valves 94 and 96, and an open failure often occurs in only one of them. Also in this case, since the hydraulic pressures of the two pressurizing chambers 36 and 38 are at the same height, both outflow prevention valves are switched to the outflow prevention state, and the same control as in the above case is performed. .

The outflow prevention valve may be an electromagnetic on-off valve. As shown in FIG. 8, in the present brake device, electromagnetic on-off valves 300 and 301 as outflow prevention valves are provided in the middle of the liquid passages 66 and 67, respectively.
In the present embodiment, the solenoid on-off valves 300 and 301 are
As described above, when the brake fluid pressure is lower than the value obtained by multiplying the master pressure by the set value, the cutoff state is switched. When it is detected that the master shut-off valves 94 and 96, which should be in the shut-off state, are open, the state is switched to the shut-off state, and it is actually detected that the outflow control device 75 is in the outflow allowable state. Do not mean.

Further, instead of detecting the open failure of the master shut-off valves 94 and 96 based on the relationship between the master pressure and the brake fluid pressure, the open failure is detected based on the relationship between the brake operating force and the master pressure. be able to. As described above, when the brake operation force is the same, at the time of the opening failure, the master pressure becomes higher than the normal case by the reaction force of the stopper 71. Therefore, an open failure can be detected based on the relationship between the master pressure and the operating force. Further, the open failure can be detected based on the relationship between the operation stroke of the brake pedal 34 and the master pressure. As shown in FIG. 9, the operating stroke and the master pressure PM
If C belongs to the region R, it can be determined that an open fault has occurred. In the present embodiment, since the stroke simulator 78 is provided, the master shutoff valve 94,
Even when 96 is in the cutoff state, a change in the stroke of the brake pedal 34 is allowed, and a reaction force according to the operation force is applied. The brake operation can be performed with the same feeling as when the master shut-off valves 94 and 96 are in communication, and the open failure of the master shut-off valves 94 and 96 is detected based on the relationship between the operation stroke and the master pressure. You can.

The electromagnetic on-off valve 132 is not a simple on-off valve, but may be a linear valve that opens at an opening corresponding to the amount of supplied current. Further, the structure of the brake device is not limited to that in the above embodiment. The rear side of the control piston 106 in the hydraulic pressure control cylinder 12 can communicate with the atmosphere. FIG. 10 shows an example of the brake device in that case. In the present embodiment, the second volume chamber 88 of the stroke simulator 78 is connected to the reservoir 54 by the liquid passage 320, and the electromagnetic on-off valve 13
2 are provided. The solenoid on-off valve 132 is the master shutoff valve 9
4, 96 are open when they are in the cutoff state, but are switched to the closed state when an open failure is detected. When the master shut-off valves 94 and 96 are open, it is not necessary to bring the stroke simulator 78 into the operation permission state, and the hydraulic fluid in the pressurizing chambers 36 and 38 is supplied to the brakes 22 and 2.
4 can be used effectively.

Further, the brake fluid pressure control device is not limited to the above embodiment. Master shut-off valve 94, 9
The structure is not limited as long as the hydraulic pressure of the brake cylinders 14 and 16 can be controlled in the shut-off state of the master shut-off valves 94 and 96 on the downstream side of 6. For example, in the hydraulic control cylinder 12, the control piston 106 can be moved based on the hydraulic pressure of the rear chamber 128 instead of the operation of the control motor 100. Rear room 1
A power hydraulic pressure source including a pump and a hydraulic pressure control valve device capable of controlling the hydraulic pressure of the hydraulic fluid discharged from the pump is connected to 28. The hydraulic pressure in the rear chamber 128 is controlled by the control of the hydraulic pressure control valve device, and the control piston 10 is controlled.
6 and 108, the hydraulic pressure in the control pressure chambers 120 and 122 is controlled. It is not essential to include the hydraulic control cylinder 12. The above-described powered hydraulic pressure source may be connected to the fluid passages 90, 92 downstream of the master shutoff valves 94, 96. The powered hydraulic source may include an accumulator or may include two or more pumps. Further, the hydraulic pressure of the brake cylinders 14, 16 can be controlled by controlling the hydraulic pressure control valve devices 166, 168. In this case, the hydraulic pressure control valve devices 166 and 168 and the pump 1 as a power drive source
A brake fluid pressure control device is constituted by 82 and the like.

The control of the brake fluid pressure may be performed based on the target deceleration. further,
The brake fluid pressure may always be controlled based on the pedaling force detected by the pedaling force sensor 212 irrespective of whether or not the master shut-off valves 94 and 96 have an open failure. In addition, the present invention can be embodied by various modifications and improvements by those skilled in the art, in addition to the aspects described in the section of “Problems to be Solved by the Invention, Problem Solving Means and Effects”.

[Brief description of the drawings]

FIG. 1 is a circuit diagram (partially sectional view) of a brake device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a brake fluid pressure control device included in the brake device.

FIG. 3 is a flowchart showing a brake control program stored in a ROM of the brake fluid pressure control device.

FIG. 4 is a diagram showing a table for determining a target brake fluid pressure stored in a ROM of the brake fluid pressure control device.

FIG. 5 is a diagram showing a table for determining a target brake fluid pressure stored in a ROM of the brake fluid pressure control device.

FIG. 6 is a conceptual diagram showing a structure of an outflow prevention valve of the brake device.

FIG. 7 is a conceptual diagram showing a structure of an outflow prevention valve of a brake device according to another embodiment of the present invention.

FIG. 8 is a circuit diagram (partially sectional view) of a brake device according to another embodiment of the present invention.

FIG. 9 is a diagram showing a relationship between an operation stroke and a master pressure when detecting an open failure of a master shutoff valve in a brake fluid pressure control device included in a brake device according to still another embodiment of the present invention. is there.

FIG. 10 is a circuit diagram (partially sectional view) of a brake device according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Master cylinder 12 Hydraulic control cylinder 14, 16 Brake cylinder 75 Outflow control device 78 Stroke simulator 100 Control motor 132 Electromagnetic on-off valve 148, 150, 250, 300, 301 Outflow prevention valve

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kyoji Mizutani F-term (reference) 3D046 BB01 CC02 DD03 FF04 HH02 HH16 HH36 KK12 LL02 LL05 LL23 LL37 LL46 MM03 MM04 MM15, Toyota Motor Co., Ltd. 1 Toyota Town, Aichi Prefecture 3D047 BB08 CC22 CC27 DD03 FF04 FF22 HH10

Claims (9)

[Claims] 1. A low-pressure source for storing a hydraulic fluid at substantially atmospheric pressure, (a) a housing, and (b) a liquid-tight and slidably fitted to the housing and operated based on an operation of a brake operating member. A pressurizing piston for generating a hydraulic pressure in the pressurizing chamber in front thereof in accordance with the operation state of the brake operating member,
(c) a master cylinder including an outflow control device that allows the flow of the hydraulic fluid from the pressurizing chamber to the low-pressure source while the pressurizing piston is at the retracted end position, and blocks the flow in the other state; The outflow control device is provided between a master cylinder and a low-pressure source, and when the hydraulic pressure in the pressurizing chamber is abnormally high in relation to an operation state of the brake operating member, the outflow control device is configured to output the low-pressure from the pressurizing chamber. A brake device comprising: an outflow prevention device that prevents the hydraulic fluid from flowing out of the pressurized chamber to the low-pressure source even when the hydraulic fluid is allowed to flow out to the source. 2. A brake cylinder for a hydraulically actuated brake, provided between the brake cylinder and the pressurizing chamber,
A master shut-off valve that can be switched between a shut-off state for shutting off these and a communication state for communication, and a master shut-off valve that is provided between the master shut-off valve and the brake cylinder; A brake fluid pressure control device that controls a pressure based on the brake operation state, wherein the outflow prevention device is configured such that the brake fluid pressure control device causes the fluid pressure of the brake cylinder to be higher than the fluid pressure of the pressurizing chamber. When the hydraulic pressure of the brake cylinder is lower than a height determined based on the hydraulic pressure of the pressurizing chamber of the master cylinder, the hydraulic fluid from the pressurizing chamber to the low-pressure source is controlled when The brake device according to claim 1, further comprising an outflow prevention valve that prevents outflow. 3. A brake cylinder for a hydraulically actuated brake, provided between the brake cylinder and the pressurizing chamber,
A master shut-off valve that can be switched between a shut-off state for shutting off these and a communication state for communication, and a master shut-off valve that is provided between the master shut-off valve and the brake cylinder; A brake fluid pressure control device that controls the pressure based on the brake operation state, and wherein the outflow prevention device is configured to control the hydraulic pressure of the brake cylinder by the hydraulic pressure of the pressurized chamber by the brake fluid pressure control device. When the hydraulic pressure in the pressurizing chamber of the master cylinder is higher than a height determined based on an operating force of the brake operating member and a predetermined relationship, the pressurizing chamber may be controlled in a higher state. The brake device according to claim 1, further comprising an outflow prevention valve configured to prevent outflow of the hydraulic fluid from the hydraulic fluid to the low-pressure source. 4. A brake cylinder for a brake operated by hydraulic pressure, and provided between the brake cylinder and the pressurizing chamber.
A master shut-off valve that can be switched between a shut-off state for shutting off these and a communication state for communication, and a master shut-off valve that is provided between the master shut-off valve and the brake cylinder; A brake fluid pressure control device that controls pressure, and a stroke simulator that allows a change in an operation stroke of the brake operation member in a shut-off state of the master shut-off valve and applies a reaction force according to an operation force, and In the case where the outflow prevention device is to be controlled by the brake fluid pressure control device so that the brake fluid pressure is higher than the pressure chamber of the master cylinder, the fluid pressure of the pressure chamber is reduced by the brake operation member. When the hydraulic pressure is higher than the hydraulic pressure determined based on the operation stroke, the outflow prevention for preventing the hydraulic fluid from flowing out from the pressurizing chamber to the low pressure source. Brake device according to claim 1, characterized in that it comprises a valve. 5. The outflow preventing device according to claim 1, wherein said outflow preventing device is configured to prevent an outflow of the hydraulic fluid from said pressurizing chamber to said low pressure source in accordance with a supply current to said coil, and to allow an outflow. 5. The brake device according to claim 1, further comprising a switchable electromagnetic control valve. 6. A low-pressure source for storing a hydraulic fluid at substantially atmospheric pressure, (a) a housing, and (b) a liquid-tight and slidably fitted to the housing and operated based on an operation of a brake operating member. Pressurized piston, and (c) an outflow control device that allows the flow of hydraulic fluid from the pressurized chamber to the low-pressure source when the pressurized piston is at the retracted end position, and blocks the flow in other states. A master cylinder including the master cylinder and the low pressure source, the outflow control device being configured to permit the outflow of the hydraulic fluid from the pressurization chamber to the low pressure source when the pressurization is performed. A movable member that is operated in accordance with the hydraulic pressure of the chamber, and prevents the hydraulic fluid from flowing out of the pressurizing chamber to a low-pressure source when the hydraulic pressure of the pressurizing chamber is equal to or higher than a predetermined set pressure. A brake device comprising a pilot-type outflow prevention valve. 7. A housing comprising: (i) a housing; (ii) a simulator piston liquid-tightly and slidably fitted to the housing to partition the interior of the housing into two volume chambers; Urging means disposed in a state of urging in a direction to decrease the volume of one of the first volume chambers, the pressurizing chamber being connected to the first volume chamber, A stroke simulator in which the low-pressure source is connected to the second volume chamber, a cut-off state provided between the second volume chamber and the low-pressure source, and the second volume chamber is cut off from the low-pressure source; The brake device according to any one of claims 1 to 6, further comprising a simulator device that includes a simulator control valve that switches to a communication state in which the two-volume chamber communicates with the low-pressure source. 8. An operation force detection unit for detecting a brake operation force applied by a driver to the brake operation member, wherein the brake fluid pressure control device includes: a low-pressure power source; An operating force-responsive brake fluid pressure control unit that controls the brake fluid pressure based on the brake operating force detected by the operating force detecting unit when in a flow-out preventing state that blocks the flow of the hydraulic fluid to the operating force detecting unit. The brake device according to any one of claims 2 to 5, wherein: 9. A low-pressure source for storing a hydraulic fluid at substantially atmospheric pressure, (a) a housing, and (b) a liquid-tight and slidably fitted to the housing and operated based on an operation of a brake operating member. A pressurizing piston for generating a hydraulic pressure in the pressurizing chamber in front thereof in accordance with the operation state of the brake operating member,
(c) a master cylinder including an outflow control device that permits the flow of the hydraulic fluid from the pressurizing chamber to the low-pressure source when the pressurizing piston is at the retracted end position, and blocks the flow in the other state; A brake cylinder of a brake operated by pressure, and a brake cylinder provided between the brake cylinder and the pressurizing chamber;
A master shut-off valve that can be switched between a shut-off state for shutting off these and a communication state for communication, and a master shut-off valve that is provided between the master shut-off valve and the brake cylinder; A brake fluid pressure control device that controls a pressure based on the brake operation state; a master shutoff valve abnormality possibility detection unit that detects a possibility that the master shutoff valve is abnormal; and between the master cylinder and a low pressure source. When the master shut-off valve abnormality possibility detection unit detects that the master shut-off valve may be abnormal, the outflow control device controls the flow of the hydraulic fluid from the pressurizing chamber to the low-pressure source. A brake device for preventing a flow of the hydraulic fluid from the pressurizing chamber to the low-pressure source even when the brake device is allowed.